Santa Barbara County grew by only 0.2% from 2000-2005, while California on the whole grew over 7%. The percentage of Latinos grew to 37.3%, indicating that other racial groups experienced a decline in actual numbers. 54.1% of the population is Non-Hispanic White. The African American percentage remained steady and the percentage of Native Americans rose to 1.6%. 4.6% of the population was Asian. Only 2.2% of the population reported two or more races.
As of the census of 2000, there were 399,347 people, 136,622 households, and 89,487 families residing in the county. The population density was 146 people per square mile (56/km²). There were 142,901 housing units at an average density of 52 per square mile (20/km²). The racial makeup of the county was 72.72% White, 2.30% Black or African American, 1.20% Native American, 4.09% Asian, 0.18% Pacific Islander, 15.20% from other races, and 4.31% from two or more races. 34.22% of the population were Hispanic or Latino of any race. 9.1% were of German, 8.5% English and 6.5% Irish ancestry according to Census 2000. 26.58% of the population reported speaking Spanish at home.
There were 136,622 households out of which 32.4% had children under the age of 18 living with them, 51.4% were married couples living together, 10.0% had a female householder with no husband present, and 34.5% were non-families. 24.3% of all households were made up of individuals and 9.4% had someone living alone who was 65 years of age or older. The average household size was 2.8 and the average family size was 3.33.
In the county the population was spread out with 24.9% under the age of 18, 13.3% from 18 to 24, 29.0% from 25 to 44, 20.1% from 45 to 64, and 12.7% who were 65 years of age or older. The median age was 33 years. For every 100 females there were 100.1 males. For every 100 females age 18 and over, there were 98.1 males.
The median income for a household in the county was $46,677, and the median income for a family was $54,042. Males had a median income of $37,997 versus $29,593 for females. The per capita income for the county was $23,059. About 8.5% of families and 14.3% of the population were below the poverty line, including 16.3% of those under age 18 and 6.2% of those age 65 or over.
The population of the area south of the Santa Ynez Mountain crest—the portion known as "South County"—was 201,161 according to the 2000 census; thus the population is almost exactly split between north and south. Recent years have shown slow or even negative growth for regions in the south county, while areas in the north county have continued to grow at a faster rate.
Santa Barbara County is served by Amtrak trains and Greyhound Lines buses. The southern portion of the county is served by the Santa Barbara Metropolitan Transit District. In the North County, the cities of Lompoc, Santa Maria, and Buellton/Solvang have their own bus services.
Commercial flights are available at Santa Barbara Airport and Santa Maria Public Airport.